Blower wheel with improved wheel hub to blade interface

ABSTRACT

A blower wheel for use in a blower assembly includes a hub, a concentrically arranged outer ring, an array of spaced apart blades extending between the hub and the outer ring. The hub includes an outer first surface and an inner second surface. An interface between an outer edge of a first end of each of the blades and an outer peripheral edge of the outer first surface of the hub is minimized, increasing an effective blade exit height of the blower wheel. As such, an effective open area for airflow between the blades of the blower wheel is increased over that of the prior art blower wheels. Further, a substantially planar lower face of the hub provides additional structural integrity to the hub, and thereby the blades.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/668,175 filed Jul. 5, 2012, the entire disclosure of which is hereby incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a blower wheel and more particularly to a blower wheel having a plurality of blades which maximizes airflow through the blades and optimizes efficiency thereof.

BACKGROUND OF THE INVENTION

Centrifugal blowers are commonly used for directing a forced flow of air through an air duct. In a typical blower assembly, air is drawn into a housing through an air inlet and discharged from the housing through an air outlet. Blower assemblies typically include an electrically driven blower wheel that rotates in a predetermined direction in the housing. The blower wheel includes one or more curved blades coupled to a hub, which draw the air into the blower wheel axially along an axis of rotation and discharge the air radially outwardly therefrom.

Typically, in climate control applications such as heating, ventilating, and air conditioning (HVAC) systems of a vehicle, the centrifugal blowers are required to operate effectively and efficiently over a range of operating conditions of the vehicle. However, an interface between the blades and the hub of current centrifugal blowers is configured in such a manner that blockage results in a reduction of effective open area for a flow of air between the blades.

Accordingly, it would be desirable to produce a blower wheel that maximizes performance, efficiency, and structural integrity, while minimizing a cost and a complexity thereof.

SUMMARY OF THE INVENTION

In concordance and agreement with the present invention, a blower wheel that maximizes performance and structural integrity, while minimizing a cost and a complexity thereof, has surprisingly been discovered.

In one embodiment, the blower wheel comprises: a hub having a first surface and an outer peripheral edge; an outer ring concentric with and spaced from the hub; and at least one blade extending between the hub and the outer ring, wherein a thickness of the outer peripheral edge is less than about 2.5 mm.

In another embodiment, the blower wheel comprises: a hub having an outer surface and an outer peripheral edge; an outer ring concentric with and spaced from the hub; and at least one blade extending between the hub and the outer ring, wherein an effective blade exit height of the at least one blade is substantially equal to a total blade exit opening of the at least one blade.

In yet another embodiment, the blower wheel comprises: a hub having an inner surface, an outer surface, and an outer peripheral edge; an outer ring concentric with and spaced from the hub; and at least one blade extending between the hub and the outer ring, wherein at least one of the outer surface of the hub terminates at a substantially planar outer face and the inner surface of the hub terminates at a substantially planar inner face.

DESCRIPTION OF THE DRAWINGS

The above, as well as other objects and advantages of the invention, will become readily apparent to those skilled in the art from a reading of the following detailed description of a preferred embodiment of the invention when considered in the light of the accompanying drawings in which:

FIG. 1 is a fragmentary cross-sectional elevational view of a blower wheel according to an embodiment of the invention; and

FIG. 2 is a fragmentary cross-sectional elevational view of a blower wheel according to another embodiment of the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner.

FIG. 1 a shows a blower wheel 10 according to the present invention. The blower wheel 10 can be used in any blower assembly as desired such as a blower assembly for an air conditioning unit of a vehicle, for example. Typically, the blower wheel 10 is disposed within a housing (not shown) and rotatably coupled to a motor (not shown) for causing a rotational movement of the blower wheel 10 within the housing. It is understood, however, that the blower wheel 10 can be caused to rotate by any manual or automatic means as desired. The rotational movement of the blower wheel 10 in a first direction causes a flow of air received in an air inlet of the housing to flow at an increased dynamic pressure in a radially outward direction. The blower wheel 10 shown can be formed from any suitable material as desired such as a plastic material, for example.

As illustrated, the blower wheel 10 includes an annular array of spaced apart blades 12 extending between a hub 14 and a concentrically arranged outer ring 16. In certain embodiments, the blades 12 are arranged on the hub 14 at equal intervals with respect to an axis of rotation of the blower wheel 10, although other intervals can be employed. Additional or fewer blades 12 than shown can be employed if desired. Each of the blades 12 includes a substantially linear leading edge 18 and a substantially linear trailing edge 20 extending from the hub 14 to the outer ring 16. Each of the blades 12 further includes a first surface 22 and an opposed second surface (not shown). In certain embodiments, the first surface 22 has a substantially concave shape in the direction of rotation of the blower wheel 10 and the second surface has a substantially convex shape in the direction of rotation of the blower wheel 10. It is understood that the first surface 22 and the second surface can have any shape as desired such as a substantially concave shape in the direction of rotation of the blower wheel 10, a substantially convex shape in the direction of rotation of the blower wheel 10, or a substantially planar shape, for example.

The hub 14 is generally dome-shaped having an outer first surface 24, a coextensive inner second surface 26, and a nose portion 27 formed at an apex thereof. The nose portion 27 can have any shape and size as desired. Each of the outer first surface 24 and the inner second surface 26 is generally arcuate at an outer peripheral edge 28 of the hub 14. A substantially planar face 30 of the outer peripheral edge 28 extends between the surfaces 24, 26 and is formed substantially perpendicular to an axis of rotation of the hub 14. A width (W) of the substantially planar face 30 of the hub 14 provides additional structural integrity to the hub 14, and thereby the blades 12. As a non-limiting example, the width (W) of the substantially planar face 30 is in a range of about 0.5 mm to about 2.5 mm. It is understood, however, that the substantially planar face 30 can have any width (W) as desired.

Each of the blades 12 has a first end 31 extending from the leading edge 18 to the trailing edge 20. A portion of the first end 31 adjacent the leading edge 18 is configured to conform to a shape and contour of the outer first surface 24. A distance from an outer edge 32 of the first end 31 of one or more of the blades 12 to the outer edge 29 of the outer ring 16 is characterized as a total blade exit opening (TBD). The total blade exit opening (TBO) is an actual height of open area for airflow between the blades 12. An effective blade exit height (EBH) is substantially equal to the total blade exit opening (TBO) minus a thickness of the outer peripheral edge 28.

In the present invention, an interface between the outer edge 32 of the first end 31 of each of the blades 12 and the outer first surface 24, and more particularly the outer peripheral edge 28, of the hub 14 is minimized, increasing the effective blade exit height (EBH) over prior art blower wheels. As shown, the thickness of the outer peripheral edge 28 of the hub 14 is less than about 2.5 mm, essentially 0.0 mm. As such, the effective blade exit height (EBH) is substantially equal to the total blade exit opening (TBO), which results in increase of about 3.5% to about 4% in an effective open area for airflow between the blades 12 over the prior art blower wheels. Various configurations of the effective blade exit height (EBH) and the width (W) of the substantially planar face 30 can be employed to maximize performance and structural integrity of the blower wheel 10.

FIG. 2 shows another embodiment of the blower wheel 10 illustrated in FIG. 1. Structure similar to that illustrated in FIG. 1 includes the same reference numeral and a single prime (′) symbol for clarity. As illustrated, a blower wheel 10′ includes an annular array of spaced apart blades 12′ extending between a hub 14′ and a concentrically arranged outer ring 16′. In certain embodiments, the blades 12′ are arranged on the hub 14′ at equal intervals with respect to an axis of rotation of the blower wheel 10′, although other intervals can be employed. Additional or fewer blades 12′ than shown can be employed if desired. Each of the blades 12′ includes a substantially linear leading edge 18′ and a substantially linear trailing edge 20′ extending from the hub 14′ to the outer ring 16′. Each of the blades 12′ further includes a first surface 22′ and an opposed second surface (not shown). In certain embodiments, the first surface 22′ has a substantially concave shape in the direction of rotation of the blower wheel 10′ and the second surface has a substantially convex shape in the direction of rotation of the blower wheel 10′. It is understood that the first surface 22′ and the second surface can have any shape as desired such as a substantially concave shape in the direction of rotation of the blower wheel 10′, a substantially convex shape in the direction of rotation of the blower wheel 10′, or a substantially planar shape, for example.

The hub 14′ is generally dome-shaped having an outer first surface 24′, a coextensive inner second surface 26′, and a nose portion 27′ formed at an apex thereof. The nose portion 27′ can have any shape and size as desired. At the outer peripheral edge 28′ of the hub 14′, the outer first surface 24′ terminates at a substantially planar outer first face 40 and the inner second surface 26′ terminates at a substantially planar inner second face 42. As illustrated, the outer first face 40 is formed substantially parallel to the inner second face 42, and each of the faces 40, 42 is formed substantially parallel to the axis of rotation of the hub 14′. It is understood, however, that the faces 40, 42 can be formed in any configuration and orientation as desired. A substantially planar third face 44 extends between the faces 40, 42 and is formed substantially perpendicular to the axis of rotation of the hub 14′. A width (W′) of the third face 44 of the hub 14′ provides additional structural integrity to the hub 14′, and thereby the blades 12′. As a non-limiting example, the width (W) of the third face 44 is in a range of about 0.5 mm to about 2.5 mm. It is understood, however, that the third face 44 can have any width (W) as desired.

Each of the blades 12′ has a first end 31′ extending from the leading edge 18′ to the trailing edge 20′. A portion of the first end 31′ adjacent the leading edge 18′ is configured to conform to a shape and contour of the outer first surface 24′. A distance from an outer edge 32′ of the first end 31′ of one or more of the blades 12′ to the outer edge 29′ of the outer ring 16′ is characterized as a total blade exit opening (TBO′). The total blade exit opening (TBO′) is an actual height of open area for airflow between the blades 12′. An effective blade exit height (EBH′) is substantially equal to the total blade exit opening (TBO′) minus a thickness (T) of the outer peripheral edge 28′.

In the present invention, an interface between the outer edge 32′ of the first end 31′ of each of the blades 12′ and the outer first surface 24′, and more particularly the outer peripheral edge 28′, of the hub 14′ is minimized, increasing the effective blade exit height (EBH′) over prior art blower wheels. As shown, the thickness T of the outer peripheral edge 28′ of the hub 14′ is less than about 2.5 mm, specifically in a range of about 0.5 mm to about 1.5 mm. As such, the effective blade exit height (EBH′) is minimally smaller than the total blade exit opening (TBO′), which results in increase of about 2.0% to about 3% in an effective open area for airflow between the blades 12′ over the prior art blower wheels. Various configurations of the effective blade exit height (EBH′) and the width (W′) of the third face 44 can be employed to maximize performance and structural integrity of the blower wheel 10′.

An operation of the blower wheel 10′ is substantially similar to an operation of the blower wheel 10. For simplicity, only the operation of the blower wheel 10 is described hereinafter.

In use, the blower wheel 10 is driven by the motor and caused to rotate about the axis of rotation. The rotation of the blower wheel 10 causes the air to flow through the air inlet of the housing. The blades 12 cause a change of direction of the air from a substantially axial direction parallel to the axis of rotation of the blower wheel 10 to a substantially radial direction perpendicular to the axis of rotation. Accordingly, the air flows axially through the air inlet into the blower wheel 10, and then flows radially outwardly from the blower wheels 10 through the effective open area between the blades 12 and into a scroll duct of the housing. Thereafter, the air flows out of the housing to a desired area.

From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions. 

1. A blower wheel comprising: a hub having a first surface and an outer peripheral edge; an outer ring concentric with and spaced from the hub; and at least one blade extending between the hub and the outer ring, wherein a thickness of the outer peripheral edge is less than about 2.5 mm.
 2. The blower wheel of clam 1, wherein an effective blade exit height of the at least one blade is substantially equal to the total blade exit opening of the at least one blade.
 3. The blower wheel of claim 1, wherein the thickness of the outer peripheral edge is in a range of about 0.0 mm to about 1.5 mm.
 4. The blower wheel of claim 1, wherein the first surface of the hub is generally arcuate at the outer peripheral edge thereof.
 5. The blower wheel of claim 1, wherein at least one of the first surface of the hub terminates at a substantially planar first face and a second surface of the hub terminates at a substantially planar second face.
 6. The blower wheel of claim 5, wherein the first face is substantially parallel to the second face.
 7. The blower wheel of claim 5, wherein at least one of the first face and the second face is substantially parallel to an axis of rotation of the hub.
 8. The blower wheel of claim 5, wherein the hub includes a substantially planar third face extending between the first face and the second face.
 9. The blower wheel of claim 8, wherein the third face is substantially perpendicular to an axis of rotation of the hub.
 10. The blower wheel of claim 8, wherein a width of the third face of the hub is in a range of about 0.5 mm to about 2.5 mm.
 11. A blower wheel comprising: a hub having an outer surface and an outer peripheral edge; an outer ring concentric with and spaced from the hub; and at least one blade extending between the hub and the outer ring, wherein an effective blade exit height of the at least one blade is substantially equal to a total blade exit opening of the at least one blade.
 12. The blower wheel of claim 11, wherein the outer surface of the hub is generally arcuate at the outer peripheral edge thereof.
 13. The blower wheel of claim 11, wherein the hub includes a substantially planar face.
 14. The blower wheel of claim 13, wherein a width of the face of the hub is in a range of about 0.5 mm to about 2.5 mm.
 15. A blower wheel comprising: a hub having an inner surface, an outer surface, and an outer peripheral edge; an outer ring concentric with and spaced from the hub; and at least one blade extending between the hub and the outer ring, wherein at least one of the outer surface of the hub terminates at a substantially planar outer face and the inner surface of the hub terminates at a substantially planar inner face.
 16. The blower wheel of claim 15, wherein a thickness of the outer peripheral edge is in a range of about 0.5 mm to about 1.5 mm.
 17. The blower wheel of claim 15, wherein the outer face is substantially parallel to the inner face.
 18. The blower wheel of claim 15, wherein the hub includes a substantially planar lower face extending between the outer face and the inner face.
 19. The blower wheel of claim 18, wherein the lower face is substantially perpendicular to an axis of rotation of the hub.
 20. The blower wheel of claim 18, wherein a width of the lower face of the hub is in a range of about 0.5 mm to about 2.5 mm. 